Optical Printing of Gold nanoparticles: an interplay between nanosclae optical and thermal forces.

GARGIULO, JULIÁN; BRICK, THOMAS; STEFANI, FERNANDO D.; ZAZA, CECILIA; MAIER, STEFAN A.; VIOLI, IANINA L.; CORTÉS, EMILIANO

Porquerolles Island

Workshop; Photothermal Effects in Plasmonics; 2018

Among the various methods for decorating surfaces with colloidal nanoparticles (NPs), Optical Printing stands out because it enables the fabrication of patterns of arbitrary design on plane substrates with no need of any previous steps of physical or chemical patterning. By means of optical forces, Au NPs can be positioned with an accuracy higher than 50 nm. However, it was not possible to print identical NPs closer to each other than 300 nm. Light absorption by printed NPs and subsequent local heating produces photothermal forces that compete with the optical and disturb the printing process. Here we model and quantify these photothermal effects considering thermophoretic and thermos-osmotic forces. By optimizing heat dissipation, we demonstrate for the first time optical printing of connected NPs.